Rotary earth drilling bit



July 10, 1962 E. G. GAULT ETAL ROTARY EARTH DRILLING BIT Filed Sept. 19,1958 FIG. 4

INVENTORS ERROL. GLENN GAULT THOMAS GLENN GAULT BY aki ATTORNEY FIG.

' bore hole wall.

United States Gault, deceased Filed Sept. 19, 1958, Ser. No. 762,168 3Claims. (Cl. 175-385) This invention relates to a rotary earth drillingbit, and more particularly such a bit designed for use in drilling holesfor geophysical exploration, although this invention is capable ofgeneral earth boring use.

In bits of the character described, a shank attachable to a drillingpipe has blades to form the bore hole, and this bit is provided withwater courses whereby a drilling fluid, such as a bentonite fluid orwater or even air, is forced down the hollow drill pipe and issuesthrough the water courses. The bit is of larger diameter than the drillpipe, so that there will be a space between the drill pipe and the Thedrilling fluid issuing through the water courses, carries the cuttingsupwardly and to the surface where the cuttings will be separated in anysuitable manner as by settling or by screens. The drilling fluid is thenagain recirculated.

One of the objects of this invention is to provide a rotary earthdrilling bit which is simple in construction, eflicient in its actionand rugged.

Further objects will appear from the detailed description in which willbe set out an illustrative embodiment of this invention; it is to beunderstood, however, that this invention is capable of variousembodiments within the scope of the appended claims.

Generally stated and in accordance with the illustrative embodiment, thebit comprises a shank attachable to a drill pipe, with a series ofblades extending downwardly from the shank and extending radiallytherefrom in angular spaced relation around the bit, the tips of theblades terminating in spaced relation to the axis of the bit to leave awater course between the tips. The face of each blade extends generallyradially but is inclined from the heel to the tip of the blade in thedirection of rotation of the bit with respect to an axial plane. Bridgesremoved from the tips, connect the blades to leave additional watercourses between the heels and the tips of the blades. This, moreover,provides a rugged construction in that the blades are not subject todistortion. The tip of each blade is formed into a point extendingaxially and radially outwardly, and the cutting edge of each bladeformed of parts which are in angular relation radially; but the parts onthe several blades are in different angular relations in a manner ashereinafter more fully described.

Referring to the accompanying drawing:

FIG. 1 is a side view of the bit as attachable to a drill pipe to bepositioned at the bottom of the bore hole;

FIG. 2 is a bottom view of the bit looking upwardly towards the heel;

FIG. 3 is a view of the bit like FIG. 1 rotated at 90; and

FIG. 4 is a section on the line 4-4, FIG. 3.

Referring to the accompanying drawing, designates a drill pipe, which ishollow, and which is usually made up on sections coupled together bythreads. Screwed into the bottom of the drill pipe is a threaded shank11, the threads being tapered. Attached to the shank are a series ofblades 12 each inclined in spaced relation to the axis of the bit andterminating in tips 8. The shank 11 has a channel 2 to an enlargedchamber 3 which is contracted and leads to a narrow channel 13 in orderto provide a jet. As shown in FIG. 2, the tips 8 extend radiallyinwardly and terminate in radially spaced and in circumferentiallyspaced but in overlapping relation. The tips 8,

however, extend radially inwardly and into the path of the jet from thenarrow channel 13. The blades are, however, connected by bridges 14removed upwardly from the tips 8 and so as to make a rugged structure,but these bridges leave additional water courses 15 between the blades.The water courses 15 are connected to the interior enlarged channel 3 asshown in FIGS. 1 and 4.

The outer sides 12 of the blades are parallel as shown at 30, so as toform a guide for the drill as it progresses. The face 16 of each bladeextends generally radially, but is inclined from the heel 31 to the tip8 of the blade in the direction of rotation of the bit with respect toan axial plane as shown in FIG. 1. The entire cutting edge of the bladeis provided with hard metal facings 9 of tungsten carbide, which arewelded to the body of the bit structure, which is usually of steel oriron. This provides cutting edges which are slicing in their action asdistinguished from the construction where the faces of the are simplyvertical.

The tip of each blade adjacent the middle water course 3 is formed intoa point extending axially and radially outwardly, and the cutting faceof this point is formed of faced parts 18 and 19, which are in angularrelation radially and vertically to such point. In the embodimentshown,'the parts 18 and 19 on the several blades are in differentangular relations, that is the angle between the faced parts 18 and 19varies with the bit rotating in the direction of the arrow FIG. 2,progressively from blade to blade as we. proceed circumferentiallyaround the bit; as an example the angles vary progressively, asindicated in FIG. 2, and The bottom of each blade is provided withindentations 21 to provide a series of steps. Each blade is alsoprovided with channels 22 and 32 extending from the heel 31 of the bittowards the tip 8.

In use, the bit is attached to the drill pipe and proceeds to bore thebore hole 23 larger than the drill pipe. During the drilling operation,drilling fluid forced down the drill pipe passes through the narrowwater course 13 and as a jet onto the tips of the blades so as to freethe cuttings from the tips 8. The action is also one of providing a jetto the bottom of the formation and onto the cuttings. From the jet, thedrilling fluid passes upwardly through the channels 22 and 32. Thedrilling fluid also issues from the additional water courses 15 betweenthe blades and again passes upwardly through the channels 22 and 32.Finally the drilling fluid from the bottom of the hole passes upwardlyinto the space 24 outside of the drill pipe 10 and to the top of thewell.

Because of the formation of the blades, which are each inclined from theheel 31 to the tip 8' of the blade in the direction of rotation of thebit with respect to an axial plane, the action will be one of slicinginstead of simply scraping. Accordingly, the bit will remain sharperlonger than if those faces were vertical. In view of the fact that theblades terminate radially and circumferentially in spaced overlappingrelation and that the tips of the blades extend radially inwardly intothe path of the jet projected from the downwardly contracted channel 13,the jet impinging on the tips of the blades will keep them clean,particularly in formations which are gummy. As the bit proceedsdownwardly the cuts will be taken successively by the sets of cuttingedges of the parts 18 and 19 of the blades as we proceedcircumferentially in the direction of the arrow FIG. 2. Thus the cuttingparts at 120 will take a shallow cut, the cutting parts at 145 will takea deeper cut, and the cutting parts at 170 will take a still deeper cut;accordingly chattering of the bit will be reduced. The channel 2 of FIG.1 leads to the enlarged chamber 3 which is downwardly contracted to thechannel 13 terminating above the blades is adapted to project a jetdownwardly onto the blade tips.

Having thus described the invention, what is claimed and desired to besecured by Letters Patent is:

1. A rotary drilling bit, comprising, a shank attachable to a drillpipe, a series of blades each extending radially from said shank, theblades terminating radially and circumferentially in spaced overlappingrelations, each blade being provided with parts having cutting edgeswhich are in angular relation radially and vertically to a point, theangular relations between the cutting edges of successive bladesincreasing successively from blade to blade circumferentially around thebit.

2. A rotary drilling bit, comprising, a shank attachable to a drillpipe, a series of blades each extending radially from said shank, theblades terminating radially and circumferentially in spaced overlappingrelations, each blade being provided with parts having cutting edgeswhich are in angular relation radially and vertically to a point, theangular relations between the cutting edges of successive bladesincreasing successively from blade to blade circumferentially around thebit, the face of each blade extending generally radially but beinginclined from the heel to the tip of the blade in the direction ofrotation of the bit with respect to an axial plane.

3. A rotary drilling bit, comprising, a shank attachable to a drillpipe, a series of blades each extending radially from said shank, theblades terminating radially and circumferentially in spaced overlappingrelations, each blade being provided with parts having cutting edgeswhich are in angular relation radially and vertically to a point, theangular relations between the cutting edges of successive bladesincreasing successively from blade to blade circuinferentially aroundthe bit, said shank having a central downwardly contracted channeladapted to project a jet downwardly, the tips of the blades extendingradially inwardly into the path of the jet projected from said channel,and bridges connecting said blades above said tips and radially outsideof said channel, there being radial water courses located above saidbridges and connected with said channel.

References Cited in the file of this patent UNITED STATES PATENTS1,746,423 Hartman Feb. 11, 1930 1,854,911 Scott Apr. 19, 1932 1,974,664Patten Sept. 25, 1934 2,252,168 Creighton Aug. 12, 1941 2,504,978Henning Apr. 25, 1950 2,614,814 Jones et al. Oct. 21, 1952 2,656,153White Oct. 20, 1953 2,867,413 Olsen Jan. 6, 1959 2,894,726 Weaver et alJuly 14, 1959 2,950,089 Irons Aug. 23, 1960 FOREIGN PATENTS 505,080Canada Aug. 17, 1954

